Inducer Blade Angle Optimization for Cavitation Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional inducer designs fail to effectively predict and suppress cavitation instability phenomena, particularly in axial-flow and mixed-flow type impellers, due to high time and calculation costs associated with unsteady CFD methods.
Innovation Solution
A method using steady CFD to analyze and evaluate the stability of cavitation behavior in inducers with multiple blades of the same geometry, focusing on pressure distribution variations along blade surfaces to optimize inducer geometry and design parameters such as blade angle slopes and vortex types, thereby reducing cavitation instability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If unsteady CFD is used to predict and evaluate cavitation behavior stability, then prediction accuracy is improved, but calculation cost and time cost increase significantly
Solution Approach 1:
The patent creates a simplified copy of the cavitation analysis by extracting characteristic pressure distribution forms from steady CFD results and using their locations as evaluation indices. This copying approach allows predicting cavitation behavior stability without performing computationally expensive unsteady CFD simulations, thus resolving the contradiction between prediction accuracy and calculation cost
Solution Approach 2:
The patent substitutes the complex unsteady CFD mechanical simulation system with a simplified evaluation method based on steady CFD pressure distribution analysis. By replacing the time-consuming unsteady simulation with a static pressure field analysis using characteristic form locations, the method achieves comparable predictive capability with significantly reduced computational resources
2Stress or pressure
If conventional inducer design method with constant or linearly increasing blade angle is used, then head requirement is met, but cavitation instability phenomena occur
Solution Approach 1:
The patent changes the blade angle distribution parameter from constant or linear increase to a specific quadratic distribution pattern. This parameter change in the blade geometry design allows meeting the head requirement while simultaneously suppressing cavitation instability phenomena by optimizing the pressure distribution characteristics on the blade surfaces
Solution Approach 2:
The patent applies different blade angle increase rates at different radial positions (tip side versus hub side). The tip side blade angle increases at a rate of not less than 0.2, while the hub side follows different characteristics. This local differentiation in blade geometry quality allows simultaneous optimization of head generation and cavitation stability
3Productivity
If blade angle at tip side increases rapidly to meet head requirement, then suction performance is improved, but cavitation instability increases
Solution Approach 1:
The patent optimizes the blade angle parameter distribution along the blade length by specifying that the increase rate from leading edge to non-dimensional meridional location of 0.15 should be not less than 0.2. This precise parameter control allows achieving high suction performance while maintaining cavitation stability through optimized pressure distribution
Solution Approach 2:
The patent introduces dynamic optimization of blade geometry parameters based on performance requirements. By adjusting the blade angle distribution dynamically along the meridional direction and controlling the increase rate, the design adapts to simultaneously achieve high suction performance and stable cavitation behavior
Data Source
AI summary
The present invention relates to an inducer geometry which can optimize the behavior stability of cavitation in an inducer having a plurality of blades of the same geometry. In the inducer having a plurality of blades of the same geometry, a blade loading at a tip side in a front half of a blade is larger than that in a rear half of the blade; and when a blade angle from a circumferential direction of the inducer is expressed by βb (degree) and a meridional distance is expressed by m (mm), an increase rate dβb/dm of the blade angle at the tip side is not less than 0.2 from a blade leading edge to a non-dimensional meridional location of 0.15, and the increase rate dβb/dm of the blade angle at a mid-span is not less than 0.25 from the blade leading edge to the non-dimensional meridional location of 0.15.